JPH0249451Y2 - - Google Patents

Description

[Detailed explanation of the invention] [Field of industrial application] This invention relates to a burner mechanism for blast furnace pressure.
This is an improvement of a circulation type combustion device in which a part of the combustion gas is returned to the evaporator cylinder when liquid fuel is evaporated and combusted, and the combustion cylinder has a triple structure to form an air passage. On the other hand, by reducing the diameter of the flame port at the tip, the range of application is expanded to relatively heavy liquid fuel at blast furnace pressure, making blue flame combustion possible.

[Conventional technology and its problems]

Various improvements have been made to this type of combustion device in order to realize blue flame combustion, but one that has achieved relatively good results is, for example, regulating the length and diameter ratio of the combustion tube and evaporator tube. One example is a circulation type combustion device in which a part of the combustion gas is effectively returned to the evaporator cylinder (see Japanese Patent Publication No. 57-32289). However, the combustion device with the above structure has a narrow combustion range for liquid fuel, and in order to maintain good operation, various restrictions are imposed on the nature of the fuel used, the amount of combustion air supplied, and the adjustment of its speed. In addition, when the combustion amount is changed, the circulation flow of the combustion gas may sometimes decrease and good combustion may not be achieved, or the components may suffer from thermal distortion or oxidative wear due to the scorching heat of the combustion tube. There was a risk that normal operation would be inhibited.

On the other hand, in order to improve the circulation flow of the combustion gas, the diameter of the tip of the combustion tube is slightly reduced, and in order to prevent the combustion tube from burning, the combustion tube is made of a double structure.
A ``fuel oil burner'' (see Utility Model Application Publication No. 128324/1983) was also developed that allowed air to flow between them, but in all of these devices, the combustion air was supplied to the evaporator tube while still being cold. Therefore, the evaporation and combustion of the fuel within the evaporator cylinder did not occur smoothly, and in particular, blue flame combustion with relatively heavy liquid fuel could not be expected at all.

Furthermore, the earlier invention of the same applicant (Japanese Patent Application 1983-
No. 86229) proposes a triple structure combustion tube and a combustion means that reduces the diameter of the flame port at the tip, which is one of the features of the present invention.
Compared to the above-mentioned combustion tube, this burner has a larger diameter and a shorter length for the evaporator tube, resulting in less noise as a burner for low furnace pressure (furnace pressure = gas pressure inside the furnace during combustion). , has the characteristic that stable combustion can be obtained, but when used at a so-called blast furnace pressure of 5 mm or more of water column, oscillating combustion occurs due to the furnace pressure.
The drawback was that combustion became extremely unstable.

[Means for solving problems]

Therefore, in order to solve the problems of the conventional technology as described in the previous section, the present invention has been developed to provide a combustion cylinder with an inlet for liquid fuel etc. at the center of one side, and a reflux port for combustion gas at the base. In comparison with the above-mentioned combustion tube, a long and narrow evaporation tube, which has a smaller diameter but a constant length, is installed concentrically, and a refueling nozzle is exposed to the above-mentioned inlet. The device comprises a flame spout by connecting the tips of an outer cylinder and an inner cylinder that communicate with the air supply port, and reducing the diameter of the flame spout by a certain amount, while providing a partition cylinder between the outer cylinder and the inner cylinder. are provided to form passages A and B, and the air supply port and the evaporation cylinder are communicated through the passages.

Additionally, a method of attaching an oxidation promoting device to the front of the flame port was also used.

[Effect]

In the combustion device of the present invention having the above-mentioned configuration, the fuel gas at blast furnace pressure ejected from the elongated evaporator cylinder effectively creates a self-circulation flow within the combustion cylinder in relation to the opening of the inner cylinder (combustion cylinder), which has a reduced diameter. In addition to the effect of forming and burning almost completely and greatly reducing nitrogen oxides, the air sent into the combustion tube is formed by a passage formed by the outer tube, inner tube, and partition tube. While flowing and being supplied to the evaporator cylinder via A and B, it comes into contact with the high-temperature inner cylinder and is sufficiently heated, while reducing the diameter of the flame port at the tip of the inner cylinder to prevent the combustion flow from passing through. This has the effect of increasing the resistance and effectively causing a part of the heated combustion gas in the inner cylinder to flow back into the evaporator cylinder as a circulating flow due to the suction phenomenon accompanying the combustion of fuel in the evaporator cylinder.

Furthermore, a device in which an oxidation promoting device is separately attached to the flame port has an even better effect of completely eliminating the generation of unburned gas.

〔Example〕

Hereinafter, the configuration of the combustion device of the present invention will be described in more detail based on the embodiment shown in the drawings. Reference numeral 1 indicates a combustion cylinder, and the tips of an outer cylinder 2 and an inner cylinder 3 each having an air supply port 2a on the base end side. are coupled to form a flame port 3a, and the diameter of the flame port is reduced by a certain amount, while a partition tube 4 is interposed between the outer cylinder 2 and the inner cylinder 3 to form air passages A and B. be. Further, 5 is an evaporator cylinder arranged concentrically within the inner cylinder 3, and has a so-called elongated structure whose diameter is made as small as possible with respect to the combustion cylinder and has a considerable length. Further, an inlet 5a and a combustion gas recirculation port 5b are provided on the base side of the inner cylinder 3, which is continuous with the inner cylinder 3.
They are each opened.

Reference numeral 6 denotes a ventilation chamber provided between the outer cylinder 2 and the partition cylinder 4, which surrounds the oil supply nozzle N provided facing the introduction port 5a, and is connected to the base wall 2b of each cylinder.
A cover 6a is attached between 4a, and an air inflow hole 6b is provided in the circumferential surface of the cover, and a small hole 6c is provided in the front wall 4a inside the cover.

In the figure, numeral 7 indicates an ignition electrode mounted facing the tip of the nozzle N, and 8 indicates a damper for adjusting the flow rate provided between the air outlet 2a and the air blowing chamber 6.

Thus, in the combustion tube in the combustion apparatus shown in the above embodiment, air introduced into the cover 6a through the inlet hole 6b passes through the small hole 6c and flows out along the nozzle N to the inlet port 5a. During this period, the temperature of the nozzle is prevented from rising, as in the previous case, but a small hole 6 formed through the cover front wall 4a is used to prevent the temperature of the nozzle from rising.
a sufficiently restricts the amount of unheated air flowing into the inlet 5a, and most of the combustion air supplied to the evaporator cylinder 5 is sufficiently preheated while passing through the passages A and B. It is supplied to the evaporator column 5.

On the other hand, when the fuel gas ejected from the evaporator tube, which is configured to be as elongated as possible, burns in the combustion tube 1 and passes through the diameter-reduced flame port 3a at the tip of the inner tube 3,
Some unburned gas generates a self-circulating flow and burns again in the combustion chamber, reducing the amount of nitrogen oxides generated by approximately 20% compared to conventional burners.

Further, in front of the flame port at the tip of the inner cylinder, there is a normal oxidation promoting device (not shown) made of metal or ceramics that has an oxidation catalytic effect.
By properly installing the fuel tank, it is possible to completely eliminate the generation of unburned gas.

[Effect of idea]

As described above, in the combustion device of the present invention, the combustion tube 1 has a triple structure consisting of the outer tube 2, the inner tube 3, and the partition tube 4, and the combustion air passages A and B are provided between the three layers.
Therefore, the combustion air sent into the evaporator cylinder 5 is sufficiently preheated by the inner cylinder 3, and the diameter of the flame port 3a at the tip of the inner cylinder is reduced to ensure a good flow of combustion gas. This interaction with the circulation flow significantly accelerates the evaporation and combustion of the fuel in the evaporator cylinder, resulting in a stable blue flame even for relatively heavy liquid fuel at blast furnace pressure. Combustion can be achieved reliably.

In addition, the length of the combustion tube of the combustion device according to the present invention having the above structure can be significantly shortened compared to conventional products, and it is expected that materials will be saved and installation space will be effectively utilized. The airflow flowing through the passages A and B cools the outer cylinder 2 and the inner cylinder 3, which not only prevents accidents such as fires that conventionally occur due to the scorching heat of the combustion cylinder 1, but also prevents the effects of thermal distortion on the constituent members. It exhibits excellent effects in a wide range of ways, such as being able to reliably prevent such problems.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of the combustion device of the present invention. In the figure, 1... combustion tube, 2... outer tube, 3... inner tube, 4... partition tube, 5... evaporation tube.

Claims (1)

[Claims for Utility Model Registration] 1. An evaporator cylinder consisting of a combustion cylinder with an air and atomized liquid fuel inlet in the center on one side and a combustion gas recirculation port around the base is concentric. In a liquid fuel combustion device, the evaporator cylinder is configured to be as long and thin as possible, and the outer cylinder leading to the air supply port is connected to the tip of the inner cylinder. The diameter of the flame port is reduced by a certain amount, and passages A and B are formed by interposing a partition cylinder between the outer cylinder and the inner cylinder, and the air is supplied through the passage. A liquid fuel combustion device characterized by a port and an evaporator tube communicating with each other. 2. The liquid fuel combustion device according to claim 1, wherein the flame port is provided with an oxidation promoting device in front thereof.